How to grow canna lily
Overview
Canna lily is a herbaceous perennial grown for its bold, tropical foliage and vibrant flower spikes. It thrives in warm, humid conditions with consistent moisture and is ideal for filling gaps in garden beds or adding seasonal colour.
Varieties
- Canna indica — The classic species with bright red flowers and broad green leaves, widely grown in Australian gardens.
- Canna 'Tropicanna' — A popular hybrid with striking burgundy and orange striped foliage and orange flowers.
- Canna 'Australia' — A tall variety with deep red flowers and dark bronze-purple leaves, ideal for bold contrast.
Soil Preparation
Canna lily prefers rich, loamy soil with a pH of 6.0–7.0. Before planting, incorporate well-rotted compost or aged manure to boost organic matter. Ensure the soil drains freely to avoid root rot, especially in heavy clay areas.
Growing Guide
Plant canna lily rhizomes 10–15 cm deep and 30–60 cm apart in rich, well-draining soil. Choose a position with morning sun and afternoon shade in hotter zones to prevent leaf scorch. Water deeply and regularly during active growth, keeping the soil consistently moist but not waterlogged. Apply a 5–10 cm layer of organic mulch to retain moisture and suppress weeds. Divide rhizomes every 2–3 years in early spring to prevent overcrowding and maintain vigour.
Care
Feed monthly with a balanced liquid fertiliser (e.g., 10-10-10) during the growing season. Cut spent flower stems back to the base to encourage repeat blooming. Remove old, yellowing leaves and dead stems in late autumn to keep the plant tidy.
Companion Planting
Pair canna lily with other moisture-loving plants like elephant ears (Colocasia), gingers, and papyrus for a lush tropical bed. Avoid planting near drought-tolerant species such as succulents or lavender, which cannot tolerate the same high water needs.
Common Pests & Risks
Leaf roller caterpillars can cause unsightly rolled leaves; remove affected foliage by hand or apply Bacillus thuringiensis (Bt) spray. Rust fungus appears as orange pustules on leaves; improve air circulation and remove infected leaves, treating with a copper-based fungicide if severe.
Troubleshooting
Yellowing leaves: caused by overwatering or poor drainage; reduce watering and improve soil drainage. Brown leaf edges: due to insufficient water or low humidity; increase watering and mist foliage. Stunted growth: from lack of nutrients; apply a balanced fertiliser monthly. Leaf spots: fungal infection from wet foliage; water at soil level and improve air circulation. Failure to flower: from too much shade; move to a sunnier position.